Plural of Hypothesis | Definition, Spelling & Examples
The plural of “hypothesis” is hypotheses, pronounced [hahy-poth-uh-seez].
“Hypothesis” is a Greek-derived irregular plural noun that follows Greek pluralization rules. Instead of following the common pluralization rules of English, where you simply add “-s” or “-es” to the end of the word, Greek-derived words ending in “-is” are made plural by changing the “-is” to “-es.”
After analyzing the data, the team was able to confirm many of their hypotheses.
Hypothesis vs. hypotheses
A hypothesis is an assumption or explanation based on limited evidence and the starting point for further experimentation. It is a testable statement that predicts a possible outcome or relationship between variables in scientific research.
Hypotheses is the plural word of “hypothesis” and refers to multiple explanations or assumptions that are to be tested in a scientific way.
By comparing different hypotheses, the team aimed to find the most plausible explanation for the phenomenon.
What is an irregular plural noun?
People sometimes mistakenly use “hypothesises” as the plural of “hypothesis,” but that is incorrect. The word “hypothesis” is an irregular plural noun, meaning it doesn’t follow the regular rules of pluralizing by simply adding “-s” or “-es” to the end of the noun (e.g., dog/dogs or wish/wishes).
Instead, “hypothesis” follows Greek pluralization rules and changes the “-is” at the end of the singular form to “-es” to form the plural (e.g., diagnosis/diagnoses or crisis/crises).
“Hypothesis” happens to be a Greek-derived irregular plural, but there are irregular plurals that are derived from other languages such as Latin (e.g., stimulus/stimuli), Old English (e.g., man/men), and Dutch (e.g., hoof/hooves).
| Singular | Plural |
|---|---|
| matrix | matrices |
| woman | women |
| parenthesis | parentheses |
| vertex | vertices |
Another type of irregular plural is called zero plurals. This is a noun that remains the same in both the singular and plural forms.
| Singular | Plural |
|---|---|
| spacecraft | spacecraft |
| jeans | jeans |
| furniture | furniture |
| species | species |
Frequently asked questions about the plural of hypothesis
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Cove, R. (2024, October 03). Plural of Hypothesis | Definition, Spelling & Examples. Scribbr. Retrieved March 24, 2025, from https://www.scribbr.com/plurals/hypothesis-plural/
